CLOSE WAIT state Problem...

When using ARUser 5.xx with ARServer 4.xx we see the presence of sockets in the CLOSE_WAIT state. This half-open state indicates that ARServer fails to act upon the client closing the socket.

The CLOSE_WAIT state persists for 60 minutes as defined by tcp_keepalive_interval. Once the timeout occurs HP-UX probes the CLOSE_WAIT sockets and closes them. This removes the entries from netstat however the file handle is still allocated in the ARServer process (determined by using lsof).

After a number of hours (10h - 18h) the number of CLOSE_WAIT sockets and therefore unreleased file handles reaches a point where the 1024 file handle limit is reached (including normal ESTABLISHED connections).
What are the latest patches need for HPUX B.11 and what other steps can we take to prevent the CLOSE_WAIT sockets from taking up resource?